package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IUserService userService;
    @Resource
    private IFollowService followService;
    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(this::queryBlogUser);
        return Result.ok(records);
    }


    @Override
    public Result queryBlogById(Long id) {
        //1.查询blog
        Blog blog = getById(id);
        if(blog == null){
            return Result.fail("当前笔记不存在");
        }
        //2.根据userId获取用户信息
        queryBlogUser(blog);
        //4.返回结果
        return Result.ok(blog);
    }

    @Override
    public Result likeBlog(Long id) {
        //1.获取当前用户
        Long userId = UserHolder.getUser().getId();
        //2.判断当前用户是否对该帖子点过赞
        String key = RedisConstants.BLOG_LIKED_KEY + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        if(score != null){
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            if(isSuccess){
                stringRedisTemplate.opsForZSet().remove(key, userId.toString());
            }

        }else {
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            if(isSuccess){
                stringRedisTemplate.opsForZSet().add(key, userId.toString(), System.currentTimeMillis());
            }
        }
        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        String key = RedisConstants.BLOG_LIKED_KEY + id;
        //查询top5的点赞用户 zrange key 0 4;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if(top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        List<UserDTO> userDTOS = userService.query()
                .in("id", ids)
                .last("ORDER BY FIELD(id, " + idStr + ")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());

        return Result.ok(userDTOS);
    }

    /**
     * 笔记推送（推模式）
     * @param blog
     * @return
     */
    @Override
    public Result saveBlog(Blog blog) {
        //1.获取登陆用户
        Long userId = UserHolder.getUser().getId();
        blog.setUserId(userId);
        //2.保存探店笔记
        boolean isSuccess = save(blog);
        if(! isSuccess){
            return Result.fail("新增笔记失败！");
        }
        //3.查询所有粉丝
        List<Follow> follows = followService.query().eq("follow_user_id", userId).list();
        //4.将笔记id推送给所有粉丝
        for (Follow follow : follows) {
            Long fanId = follow.getUserId();
            String key = RedisConstants.FEED_KEY + fanId;
            stringRedisTemplate.opsForZSet().add(key, blog.getId().toString(), System.currentTimeMillis());
        }
        return Result.ok(blog.getId());
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //1.获取用户id
        Long userId = UserHolder.getUser().getId();
        //2.查询当前用户的收件箱
        String key = RedisConstants.FEED_KEY  + userId;
        //3.解析数据(blogId， minTime, offset)
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        if(typedTuples == null || typedTuples.isEmpty()){
            return Result.ok();
        }

        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        offset = 1;
        for (ZSetOperations.TypedTuple<String> typedTuple : typedTuples) {
            ids.add(Long.valueOf(typedTuple.getValue()));
            long score = typedTuple.getScore().longValue();
            if(minTime == score){
                offset ++;
            }else {
                minTime = score;
                offset = 1;
            }

        }
        //4.根据id查询blog
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id, " + idStr + ")").list();
        for (Blog blog : blogs) {
            //设置用户信息和是否点赞
            queryBlogUser(blog);
        }
        //5.封装并返回
        ScrollResult scrollResult = new ScrollResult();
        scrollResult.setList(blogs);
        scrollResult.setMinTime(minTime);
        scrollResult.setOffset(offset);
        return Result.ok(scrollResult);
    }

    private void queryBlogUser(Blog blog) {
        Long blogUserId = blog.getUserId();
        User user = userService.getById(blogUserId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());


        //判断用户是否已点赞
        UserDTO currentUser = UserHolder.getUser();
        if(currentUser == null){
            return;
        }
        Double score = stringRedisTemplate.opsForZSet()
                .score(RedisConstants.BLOG_LIKED_KEY + blog.getId(), currentUser.getId().toString());
        blog.setIsLike(score != null);
    }
}
